Solution: Depth-First Graph Traversal

class Program
{
    /// <summary>
    /// Method to print a DFS of a graph.
    /// </summary>
    /// <param name="graph">The graph.</param>
    /// <param name="source">Starting vertex.</param>
    public static string DFS(Graph myGraph, int source)
    {
        // Initialize all the vertices as not visited
        int V = myGraph.graph.Length;
        bool[] visited = new bool[V];
        // Create a stack for DFS
        Stack<int> stack = new Stack<int>();
        // Result string
        string result = "";
        // Push the source
        stack.Push(source);
        while (stack.Count > 0)
        {
            // Pop a vertex from stack
            source = stack.Pop();
            if (!visited[source])
            {
                result += source;
                visited[source] = true;
            }
            AdjNode temp = myGraph.graph[source];
            // Get all adjacent vertices of the popped vertex source.
            // If a adjacent has not been visited, then push it
            while (temp != null)
            {
                int data = temp.Vertex;
                if (!visited[data])
                {
                    stack.Push(data);
                }
                temp = temp.Next;
            }
        }
        return result;
    }
    // Main to test the above program
    static void Main(string[] args)
    {
        int V = 5;
        Graph g = new Graph(V);
        g.AddEdge(0, 1);
        g.AddEdge(0, 2);
        g.AddEdge(1, 3);
        g.AddEdge(1, 4);
        Console.WriteLine(DFS(g, 0));
    }
}